Many telephones employ antennas which are electrically connected to a signal processor housed in the telephone. Various design parameters of the antenna can affect the performance of the radiotelephone. For example, the size and shape of the antenna as well as the way in which the electrical traces of the antenna are interconnected with associated circuitry can impact the performance of the radiotelephone. Additionally, many of the radiotelephones are undergoing miniaturization which can complicate and impose design restraints on the antenna. For example, this miniaturization can create complex mechanical and electrical connections with other components such as the outwardly extending antenna which must generally interconnect with the housing for mechanical support, and, to the signal processor and other internal circuitry operably associated with the printed circuit board in the radiotelephone body.
In the past, portable satellite radiotelephones have employed top loaded monopole antennas, helix antennas, and multiple winding antennas to help improve signal quality. One example of such an effort is a quadrafillar helix antenna which utilizes four spaced-apart filament elements which are wound around an antenna's surface. Preferably, the filament elements are equally spaced around the circumference of the antenna. Typically, these type of elements or windings are printed on a flat material such as a flex circuit material, cut into the appropriate pattern, and then rolled to form the antenna elements. Generally stated, the seams are then joined with adhesive or tape, and circuit components are attached to one end of the wrapped antenna elements to electrically interconnect the signal processing circuit in the radiotelephone. For example, as illustrated in FIG. 1, a polyimide film 15 with conductive elements 15a thereon is rolled to form a helix. Tape 16 is used to bond the seams. End caps 17a, 17b are positioned over opposing ends of the rolled film 18. A printed circuit board 19 and coaxial connectors 20 are positioned adjacent the lower end cap 17b. The connector's 20 associated wires 20a are routed into the radiotelephone (not shown) through the radome 21 which is positioned over the above-described components.
Unfortunately, fabrication of these flexible antenna elements are typically relatively fragile and can be labor intensive. Further, the positional tolerances of the elements relative to both the antenna cover or "radome" and the roll can be difficult to control. Positional and form variance and the seam construction of the flex windings can undesirably affect the performance of the antenna. Further, attaching the electrical components to the flex circuit material can stress the attachment joint(s) and can require strain-relief designs to attempt to protect the function, durability, and reliability of the antenna.